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Schra, L. (author)An interlaboratory testing programme to evaluate the rising displacement test for stress corrosion crack (SCO growth investigations was carried out within the framework of the "Measurements and Testing" programme of the European Community under BCR contract nr. MATI CT 930038. The contribution of the NLR to the project consisted of testing of...report 1996
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Wanhill, R.J.H. (author), Schra, L. (author), 't Hart, W.G.J. (author)A comparison is made of the crack resistance (R-curve), fracture toughness and instability behaviour of candidate damage tolerant aluminiumlithium alloys, 2091 and 8090, and the widely used conventional 2024-T3 alloy. The 2091 alloy was in three heat treatment conditions, T8X, TX and TY, all artificially aged. The 8090 alloy was in the T81...report 1990
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Wanhill, R.J.H. (author), Schra, L. (author), 't Hart, W.G.J. (author)New impetus to continued use of alximinium alloys in major structural areas of aircraft has been given by the development of aluminium-lithium alloys. However, qualification of these new materials for service requires extensive testing and evaluation, preferably in international cooperative programmes. The evaluation of aluminium-lithium alloys...report 1989
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Wanhill, R.J.H. (author), Schra, L. (author)The economic life of airframes is largely determined by widespread initiation and growth of fatigue cracks at low stress intensities. Any factor reducing the low stress intensity fatigue damage rate could, if controllable, increase the structural durability. One such factor is corrosion fatigue crack arrest. Corrosion product build-up within a...report 1988
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Schra, L. (author), 't Hart, W.G.J. (author)Engineering property comparisons have been made for plate material of the newly developed aluminium alloy 2324-T39 and the widely used alloy 2024-T351. The properties considered were: tensile strength, fracture toughness, notched fatigue strength, and the resistance to fatigue crack propagation under both constant amplitude and flight simulation...report 1984
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Wanhill, R.J.H. (author), Schra, L. (author)Engineering properties of the PM alloy 7091-T7E69 and the IM alloys 7075-T73, 7175-T736, 7010-T736 and 7050-T736 were compared. The properties considered were strength, fracture toughness, fatigue strength, fatigue crack propagation resistance under constant amplitude and spectrum loading, stress corrosion crack initiation and propagation...report 1983
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't Hart, W.G.J. (author), Schra, L. (author)A comparative experimental investigation was done on the advanced plate alloys 7010-T651 from ALCAN and 7150-T6E189 from ALCOA. The mechanical properties, fracture toughness and corrosion properties were determined. The most notable finding was the excellent fracture toughness of alloy 7150-T6E189 combined with a high tensile strength. The...report 1982
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't Hart, W.G.J. (author), Schra, L. (author)The engineering properties of PM alloy X7091-T7E69 forgings were compared with those of forgings of the IM alloys 7075-T73, 7175-T736, 7050-T736 and 7010-T736. The properties considered were: strength, fracture toughness, fatigue crack propagation under constant amplitude and flight simulation loading, stress corrosion crack initiation and...report 1982
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't Hart, W.G.J. (author), Schra, L. (author)The Al-Zn-Mg-Cu alloy 7050 produced by Alcoa is a typical plate and forging alloy because of its low quench sensitivity. In order to compare this alloy with the earlier tested plate alloy 7010 an experimental programme was performed involving tensile, fracture toughness, and fatigue testing. In addition stress corrosion crack initiation and...report 1980
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't Hart, W.G.J. (author), Schra, L. (author)An experimental investigation.was performed on 80 mm thick plate material of 7OIO-T7651 and 7OIO-T73651 developed by Alcan Industries Ltd in U.K. The testing programme involved: tensile tests, fracture toughness, stress corrosion and fatigue tests. For comparison a similar investigation vas carried out on 7075-T7351 Alcoa plate material.report 1979
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Wanhill, R.J.H. (author), Schra, L. (author)The effects of flat to slant fracture transitions on flight simulation fatigue crack propagation in specimens of 7O5O aluminium alloy forgings are discussed. For specimens containing flat, shearlipped, or full slant fractures at similar crack lengths the crack resistance (R curve) approach appears to provide an explanation for differences in the...report 1976
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Schra, L. (author), van Leeuwen, H.P. (author)The effect of variety of heat treatments on various engineering properties was studied with the aim to derive an optimum heat treatment. The engineering properties comprised Vickers hardness, short-time tensile strength, fatigue crack propagation resistance, fracture toughness and stress corrosion resistance. The test results were compared with...report 1976
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van Leeuwen, H.P. (author), Schra, L. (author)The literature is reviewed with respect to: - tests conducted to investigate crack re-initiation under dynamic load and arrest of a running crack - metallurgical sources of rate effects - available data for aerospace engineering materials - mechanical sources of rate effects, i.e. dynamic crack tip stresses and kinetic energy effects Conclusions...report 1975